Question

the focal length of a magnifying glass is 25 cm what is its magnifying power???
​

Answer 1

Answer:

$\huge\mathbb\fcolorbox{Purple}{pink}{⭐Answer⭐}$

The required magnification is given as 11 times.

Note: The magnification is considered such that the image is formed at the least distance of distinct vision in this case.

definition:-

Magnifying glasses typically have low magnifying power: 2×–6×, with the lower-power types being much more common. At higher magnifications, the image quality of a simple magnifying glass becomes poor due to optical aberrations, particularly spherical aberration.

Answer 2

Magnifying power is inversely related to the focal length of a lens: the bigger the focal length, the lower the magnifying power. The LDDV is a constant number, as it usually tends to be the same for people with good vision.

Formula,

$Power= \frac{1}{f} (in \: metre)$

where, f= focal length.

• For convex lens

Focal length of the convex lens (f) = 25 cm = 0.25 m

Power of the lens is given by the formula

$Power= \frac{1}{f} \: (in \: meters)$

$P= \frac{1}{0.25}$

$P=4 \: Dioptre$

For a convex lens, power of the lens is positive

Therefore the power of the lens is +4D.

• For concave lens

Focal length of the concave lens (f) = 25 cm = - 0.25 m

Power of the lens is given by the formula

$Power= \: \frac{1}{f} \: (in \: meters)$

$P= \frac{1}{ - 0.25}$

$P= - 4 \: Dioptre$

For a concave lens, power of the lens is negative

Therefore the power of the lens is (-)4D.

Project code #SPJ2